As wrapping films for use in food wrapping there have been known films made of polyvinylidene chloride, polyethylene or polyvinyl chloride as main raw material.
However, polyvinylidene chloride films are disadvantageous in that they shrink drastically under heating. Polyethylene films are disadvantageous in that when they come into contact with oily foods (e.g., cooked meat, tempura) and are heated, they melt. Polyvinyl chloride films are disadvantageous in that when they come into contact with boiled water, they undergo whitening.
On the other hand, as heat-resistant resins suitable for wrapping film there have been known aliphatic polyamide resins. Aliphatic polyamide resins exhibit excellent heat resistance and mechanical strength. However, since aliphatic polyamide resins have a high hygroscopicity, they can hardly maintain their inherent physical properties. In particular, nylon-6 and copolymer nylons such as nylon-6/6,6 and nylon-6/6,10 are disadvantageous in that .epsilon.-caprolactam as monomer component bleeds to the film surface. Therefore, the application of these aliphatic polyamide resins to food wrapping is restricted for sanitary reasons.
These wrapping films also have a cuttability problem. Wrapping films are normally served with a case such as paper tube. For use, the wrapping films are pulled to a proper length, and then cut by a cutting blade mounted thereon.
As such a cutting blade there is normally used a simple blade obtained by punching a saw blade from an iron plate having a thickness of about 0.2 mm. As the case supporting this cutting blade there is used a paper box made of a coated board with a basis weight of 350 to 700 g/m.sup.2. Such a material has an extremely low rigidity.
Wrapping films are required to be easily cut according to the user's will even with such a simple cutting mechanism. In practice, however, the case or cutting blade is subject to deformation, and the film is also subject to deformation. The film is thus often cut at a position out of the cutting blade. Specifically, when the prior art polyvinylidene chloride films have a tear somewhere upon cutting, this tear extends, causing the film to be cut obliquely, not along the cutting blade. Further, when they are cut, the prior art polyethylene films require a substantial pulling force that may not only cause the case to bent but also cause the film to be deformed.